The present invention relates to an actuator and its use for position servocontrol purposes for controlling any random positioning and orientation movement of the master arm or slave arm of a master-slave remote manipulator.
More specifically the invention relates to an actuator, which can be used in place of each of the cable or belt-operated actuators used at present and which makes it possible to provide a miniaturized master arm having the same reversibility characteristics as a master arm operated by cable or belt means.
It is known that the presently used cable or belt-operated actuators have the important advantage of being mechanically reversible, i.e. they permit both the transmission to the slave arm of a movement from the master arm and the transmission to the master arm of a resistance encountered by the slave arm, when the remote manipulator is in a force or stress return state. However, these actuators have a certain number of disadvantages, two of the most important of these being the large overall dimensions more particularly resulting from the presence of pulleys effecting the reduction for a given movement and the weakness and brittleness of the cables and belts, which involves frequent maintainance.
The first of these disadvantages makes it impossible to envisage the use of these conventional actuators, when the conditions of use of the remote manipulator necessitates e.g. a miniaturization of the master arm. This is in particular the case when the remote manipulator has to carry out underwater manipulations and when it is controlled from a small-size underwater vessel, in which the available space for the master arm can e.g. be limited to a spherical portion with a diameter of 50 cm.
With regards to the weakness of the cables or tapes, this causes operating constraints with respect to the slave arm, particularly when the remote manipulator is used in the nuclear field. Thus, it is then necessary to perform a decontamination of the slave arm or its repair in an irradiated medium, which leads in all cases to operational disadvantages.